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1.
J Anim Sci ; 99(9)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34468760

RESUMO

The main objective of this study was to evaluate the effect of peripartal administration of a commercially available nonspecific immune stimulant (mycobacterium cell wall fraction; MCWF [Amplimune, NovaVive Inc., Napanee, ON, Canada]) on the incidence of disease during early lactation and subsequent fertility of dairy cows. A second objective was to characterize the dynamics of circulating white blood cells (WBC) and metabolic markers following treatment administration. Cows in an United States Department of Agriculture (USDA) organic-certified dairy herd were blocked by parity and, based on sequential calving dates, randomly assigned to receive two injections (5 mL s.c.) of either a placebo (saline solution) as a control (CON; n = 71) or MCWF (n = 65) at enrollment (7 d before expected calving) and within 24 h after calving. Blood samples were collected from a subsample of the study population (MCWF = 16; CON = 18) for WBC count at enrollment, at day 2 post enrollment, and at days 1, 3, 7, and 14 after calving. Serum fatty acids, beta-hydroxybutyrate, and Ca concentrations were determined at days 1 and 7 postpartum (MCWF = 21; CON = 21). Main outcome variables included incidence risk of peripartal and early lactation health disorders and pregnancy at first artificial insemination (AI), at 100, and at 150 days in milk (DIM). In addition, the average daily milk yield up to 90 DIM and death and live culling before 305 DIM were compared. Treatment effects were assessed using multivariable logistic regression, time-to-event analyses, and repeated measures analysis of variance (ANOVA). A treatment effect on the incidence risk of some of the health disorders in the study was established. Incidence risk of metritis and clinical mastitis <28 DIM was smaller in MCWF than in CON cows (36.9% vs. 50.7% and 6.3% vs. 19.7%, respectively). On the contrary, the incidence risk of respiratory disease <28 DIM was smaller in CON (0%) than in MCWF (7.7%). Reproductive performance of multiparous cows was affected by MCWF administration: pregnancy at first AI and pregnancy at 100 and 150 DIM were greater in MCWF than in CON (35.6% vs. 19.2%; 51.1% vs. 25.0%; and 64.4% vs. 40.4%, respectively). Overall, median intervals from calving to pregnancy were 90 vs. 121 d in MCWF and CON cows, respectively. No treatment effects on the dynamics of circulating WBC or in postpartum metabolic status were established. No differences for milk yield or for the proportion of cows that survived up to 305 DIM were determined, although cows in MCWF left the herd earlier than cows in CON. In conclusion, incidence risks of metritis and mastitis in early lactation were smaller in cows receiving MCWF, whereas the incidence risk of respiratory disease was smaller in CON. Fertility significantly improved in MCWF compared with CON cows. As this study was performed in an organic-certified dairy, specific health and reproductive management practices may affect the external validity of the current findings.


Assuntos
Doenças dos Bovinos , Mycobacterium , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Parede Celular , Feminino , Fertilidade , Lactação , Leite , Período Pós-Parto , Gravidez , Reprodução
2.
BMC Vet Res ; 15(1): 284, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31395062

RESUMO

BACKGROUND: Calf stress at weaning and during transition to group pens represents a concern in dairy operations. Favoring natural behaviors, such as grooming, may help on reducing this challenge. Our objective was to evaluate the effect of a mechanical grooming brush on behavior and health of recently weaned calves, after transferring from individual to group housing. Two treatment groups (control [CON, n = 81]; automated brush [AB, n = 81]) were compared enrolling Holstein heifers (94 ± 7 d old) that were monitored for 20 days. Four cohorts, considering one CON and one AB group (19-20 calves/pen/cohort) were enrolled sequentially. Each calf was weighed, clinically evaluated, and affixed with a 3-D accelerometer sensor attached to the ear at enrolment. Continuous measurements (min/h) were generated for the following behaviors: Not-active, active, highly active, eating, and ruminating. Cameras for continuous video recording were installed in each pen, and calves were weighted at the last day of the study (d 20). Behavioral data were summarized as daily averages (min/h). Data was examined using repeated measures analysis for nested factors, with day as the time unit. RESULTS: Overall, calves had their first interaction with the brush within 2.5 days with a mean (SE) of 7 (±9.6) h after being transferred to group pens. A significant effect was determined for the interaction day by treatment on the time spent not-active and eating. Average not-active time was greater in CON compared to AB (22.8 ± 0.82 min/h vs. 21.7 ± 0.82 min/h), while eating time was greater in AB compared with CON (7.01 ± 0.40 min/h vs. 6.43 ± 0.40 min/h). Treatment groups had a similar weight gain and time to the first disease. CONCLUSIONS: We concluded that the use of a mechanical brush influenced behavior, reducing not-active time, while increasing eating time. The consequences of this change in activity require further investigation.


Assuntos
Criação de Animais Domésticos/instrumentação , Comportamento Animal , Bovinos/fisiologia , Animais , Feminino , Asseio Animal , Abrigo para Animais , Comportamento Social
3.
BMC Vet Res ; 15(1): 53, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30732598

RESUMO

BACKGROUND: The first month of life possess significant challenges for dairy calves due to high susceptibility to digestive diseases. The objective of this study was to evaluate the effect of prebiotic supplementation with stabilized rice bran (SRB) in milk on health, immunity, and performance of pre-weaned organic dairy calves. Holstein heifer calves (n = 90) were enrolled at 6 ± 1 days old and monitored for 28 days, from July to August 2017. Calves were randomly assigned to a control (CTR; n = 45) or a treatment group (SRB; n = 45). The CTR group received milk alone and the SRB group received 120 g of SRB per day in milk to achieve a 10% w/w dose of the total calories. Daily health evaluations were conducted to score health status and disease severity (healthy, slightly affected, moderately or severely sick) of calves, through integrated assessment of diarrhea, dehydration, attitude, and milk intake. Body weights and fecal IgA quantification were completed on the first and last day of the study. RESULTS: Overall, weight gain and fecal IgA concentrations were not affected by the dietary addition of SRB. The total number of calf-days classified as healthy or sick were not different between treatment groups. Similarly, the number of calf-days categorized as slightly affected, moderately sick, or severely sick did not differ between treatment groups. Time to event analyses indicated a tendency for a treatment effect in the time to the first moderate case of diarrhea (P = 0.08), as well as in the time to recovery from diarrhea (P = 0.052), favoring control calves. CONCLUSIONS: These results indicated that the dietary addition of SRB in milk did not have an effect in health, immunity or performance of pre-weaned dairy calves.


Assuntos
Animais Recém-Nascidos/crescimento & desenvolvimento , Bovinos/crescimento & desenvolvimento , Fibras na Dieta , Suplementos Nutricionais , Oryza , Prebióticos , Ração Animal , Animais , Diarreia/prevenção & controle , Diarreia/veterinária , Ingestão de Alimentos , Fezes/química , Imunoglobulina A/análise , Ganho de Peso
4.
PLoS One ; 13(2): e0192149, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29414986

RESUMO

Escherichia coli O157:H7 fecal shedding in feedlot cattle is common and is a public health concern due to the risk of foodborne transmission that can result in severe, or even fatal, disease in people. Despite a large body of research, few practical and cost-effective farm-level interventions have been identified. In this study, a randomized controlled trial was conducted to assess the effect of reducing the level of water in automatically refilling water-troughs on fecal shedding of E. coli O157:H7 in feedlot cattle. Pens in a feedlot in the Texas Panhandle were randomly allocated as control (total number: 17) or intervention (total number: 18) pens. Fecal samples (2,759 in total) were collected both at baseline and three weeks after the intervention, and tested for the presence of E. coli O157:H7 using immunomagnetic bead separation and selective culture. There was a strong statistical association between sampling date and the likelihood of a fecal sample testing positive for E. coli O157:H7. Pen was also a strong predictor of fecal prevalence. Despite accounting for this high level of clustering, a statistically significant association between reduced water levels in the trough and increased prevalence of E. coli O157:H7 in the feces was observed (Odds Ratio = 1.6; 95% Confidence Interval: 1.2-2.0; Likelihood Ratio Test: p = 0.02). This is the first time that such an association has been reported, and suggests that increasing water-trough levels may be effective in reducing shedding of E. coli O157:H7 in cattle feces, although further work would be needed to test this hypothesis. Controlling E. coli O157:H7 fecal shedding at the pre-harvest level may lead to a reduced burden of human foodborne illness attributed to this pathogen in beef.


Assuntos
Água Potável/microbiologia , Escherichia coli O157/isolamento & purificação , Fezes/microbiologia , Animais , Bovinos , Contagem de Colônia Microbiana , Análise Multivariada , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco , Tempo (Meteorologia)
5.
Transl Anim Sci ; 2(3): 231-240, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32704707

RESUMO

The use of milk leukocyte differential (MLD) test has been proposed as a complement to somatic cell count (SCC) to assess the presence and the severity of intramammary infection. However, detailed information regarding the behavior of MLD under different physiological or pathological stages of the cow is nonexistent. The objective was to analyze the association between milk leukocyte proportions provided by a commercial automated MLD test and multiple cow and quarter-level variables. The study population consisted of 104 Holstein cows (32 primiparous and 72 multiparous) in one farm. Cows were categorized by days in milk as early (<50 DIM; n=29), middle (50-250 DIM; n=25), and late lactation (>250 DIM; n = 50). Milk from 416 quarters was collected and analyzed for lymphocytes (LYM), neutrophils (NEU), and macrophages (MAC) counts using an automated milk fluorescence microscopy system. Concurrently, a sterile composite milk sample was collected from each cow for pathogen identification through microbiological culture. Culture results were classified as no growth (NOG), gram-negative (GN), gram-positive (GP), or other (OTH). Milk leukocyte proportions varied depending on the level of total leukocyte counts (TLC; P < 0.001). Similarly, leukocyte ratios (NEU:LYM, NEU:MAC, and phagocyte:LYM) were different for multiple TLC categories (P < 0.05). There was no association between parity number and MLD; however, cows in early lactation had the greatest proportions of NEU and LYM. Leukocyte ratios varied depending on parity number and stage of lactation. Cows in the medium milk-yield category had the smallest proportions of NEU and LYM, and there was significant variation in leukocyte ratios, depending on the level of milk yield. In healthy quarters, MLD were not associated with quarter position; however, the NEU:MAC ratio was greater in rear quarters than in front quarters. In quarters with TLC >100,000, NEU% was greater in rear quarters than in front quarters (P = 0.03). For quarters with pathogen growth, TLC was greatest for GN followed by OTH and GP (P < 0.001). Milk LD depended on the isolated pathogen group, although the magnitudes of the differences were small. Although the changes in the proportions of leukocytes in milk were associated with categories of TLC, levels of milk yield, and mastitis-causing pathogen groups, the deviations were small in magnitude. Additional research is necessary to determine the potential applications for this methodology.

6.
Am J Bot ; 104(3): 419-438, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28274947

RESUMO

PREMISE OF THE STUDY: Spermacoceae are mainly an herbaceous group in the Rubiaceae. However, a few lineages are woody and are found in a diverse range of habitat types. Three of the largest woody lineages (Arcytophyllum, Hedyotis, and Kadua) are characterized by their distribution in the moist tropical mountains and have disjunct distribution patterns with respect to their closest relatives. In this study, we explore the cases of derived woodiness in these three lineages and their diversification dynamics in the tropical mountains of Asia, the Pacific, and the Americas. METHODS: By combining phylogenetic results with wood anatomical studies, we estimated timing of origin of the three woody groups, inferred their ancestral traits and ancestral distribution ranges, analyzed their associations with the tropical upland habitat, and elucidated their diversification across tropical mountains. KEY RESULTS: The three woody clades originated and diversified from herbaceous ancestors in close association with the tropical upland habitat during the Miocene. The ancestral range for Asian-Pacific Hedyotis is Africa/Madagascar and continental Asia for Pacific Kadua. The complex geological history of tropical Asia allowed Hedyotis to diversify faster and create narrow endemics near oceans in the highlands of the Western Ghats in India, Sri Lanka, Southeast Asia including southeastern China, and New Guinea. CONCLUSIONS: The three major woody clades in Spermacoceae have gained their woodiness independently from one another, subsequent to colonization by their ancestors from a different geographic environment. The evolution and diversification along the tropical mountain orogeny is strongly linked with the formation of woody habit and many narrow endemic species.


Assuntos
Rubiaceae/genética , Evolução Biológica , Ecossistema , Filogenia , Rubiaceae/anatomia & histologia , Rubiaceae/classificação , Madeira/anatomia & histologia , Madeira/classificação , Madeira/genética
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